loop on agilent 34970 measurement

[Dennis_Knutson]

I wish I still had one of these instruments.

Before the Read function, try adding a trigger function with it set to immediate trigger.

I looked through some old code and it appears that I did some custom mods or there are functions no longer in the new libraries. In order to do a resistance measurement, all I did issue MEAS:RES? command.

[wb2nvy]

While I was waiting for your response, I did exactly that, patterning it after the Advanced Scan Example.vi. All it did was make my 34970A beep with an error and display the ol' timeout error message on my LV screen.

[billko]

wb2nvy could you post a picture of your proposed VI?  I only have LV 7.1 but I'd like to try to help.  Sorry.  😞

Oh yeah, what was the error?

Message Edited by billko on 09-25-2009 04:20 PM

[billko]

Hopefully, reading this user guide - http://cp.literature.agilent.com/litweb/pdf/34970-90003.pdf - will assist you in trying to program your instrument.  Good luck!  🙂

[wb2nvy]

billko- thanks for your offer to help. Yes, I've spent hours reading the Users' Guide, but it doesn't provide me with all the information I need. I've tried many combinations of Agilent vi's and just hardcore SCPI commands in an attempt to constantly monitor the resistance of a switch connected to channel 107 of my 34901A in a manner that doesn't open and close relays for every measurement. The switch is opened when the operator opens the lid on a piece of test equipment and closed when they close the lid,and my LV 8.5 pgm needs to know if this switch is open or closed. It seems like the Monitor vi should do it, but when set up as in my attached vi (not in a loop-just trying to get 1 successful measurement at this point) the 34970A beeps and displays error 305 - "Not able to perform requested operation. The requested operation is not valid for the specified channel." This implies that if I selected a different channel it would work. There's no reason why I can't do a resistance measurement or monitor on channel 107. I can do it in my LV program by looping on the EZ Resistance vi, but I don't want to chatter the relays like that. It may be along time before the cover is closed and my pgm can continue.

I don't have a clue what I'm doing wrong. Any help would be appreciated.

[Chris_K_]

Chapter 4 on page 93 of the manual that was linked above talks about single channel monitoring.  One note that stuck out in my mind while reading it was that it was not supported with the matrix module, and I am wondering if that is what is causing you to have problems.

I would try something like figure 3 in the following link.

Using the Agilent 34970A with LabVIEW

and configure it to read the same channel, ie put channel 107 in the scan list more than once.

Chris

[wb2nvy]

Chris, thank you for your inputs. I am not using the matrix module. Fig 3 as  you referenced is EXACTLY the way I'm currently doing it, and I DON'T WANT to do it that way because it requires opening and closing the channel 107 mux switch with every loop, and this loop may continue for an indefinite period of time. I want to eliminate the mux switch closing on every loop. I want to close the mux channel switch ONE time which connects the interlock switch in my test setup to the mux, and simply loop on the resistance measurement with "no moving parts" so to speak.

BTW, in my version of Fig 3, I list (107) only once in the channel list, not once for every iteration of the loop.

[AndrewAlford]

You should use the HP34970 EZ Conf VI once at the beginning of your program , then you can use the HP34970 Monitor VI to read the resistance in your loop. See the attached VI it is in LV2009.

Message Edited by AndrewAlford on 09-29-2009 08:44 AM

[wb2nvy]

ANDREW THANK YOU IN EXPONENTIAL NOTATION! That's EXACTLY the solution I was looking for. It works perfectly. I tried doing the same thing with Configure Resistance.vi instead of Conf EZ.vi and it didn't work. I would like to know why. Also I couldn't have done this w/o the new Agilent VI's that Dennis provided.  I would also like to know how anyone would know that you need to use the monitor.vi TWICE to get the desired output. I spent about 10 hours trying to accomplish this, reading all the documentation with the vi's and the 34970A manual,which, by the way, is absolutely WRONG in how they describe doing this with 3 lines of SCPI code. And it took quite awhile on this chat thread for someone to understand & solve the problem. If you're ever in central NY I'll buy you a beer or 3. Thanks again.